Method of sizing hydrophobic synthetic yarns



United States Patent 3,144,351 METHGD 0F SlZING HYDROPHOBIC SYNTHETHC YARNS Glenn M. Anderson, Decatur, Ga, assignor to Penick 8:

Ford, Ltd., Cedar Rapids, Iowa, a corporation of Delaware N0 Drawing. Filed Oct. 18, 1961, Ser. No. 145,962

Claims. (ill. 117-1383) This invention relates to a method of sizing hydrophobic synthetic yarns and sizing compositions which are especially adapted for use in the method. The method and compositions of this invention have particular utility in sizing polyamide yarns such as nylon, polyester yarns such as Dacron, and Kodel, and polyacrylic yarns such as Acrilan.

Sizing of spun yarns, usually called slashing, has as its primary object the adsorption and absorption of a film forming material into and on the fibers comprising the spun yarn which may be in the form of hanks or warps. This treatment imparts to the spun yarn increased tensile strength and resistance to the abrasive action of the parts of the loom that are employed in the manufacturing of woven fabric from the yarn. Thus, adequate sizing results in increased weaving efficiency by reducing the number of breaks in the warp, clinging of the ends of the warp in the shedding motion of the loom, reduction of fiber shedding at the loom and facilitates proper operation of the stop motion and other functions of the loom. In addition, adequate sizing improves the quality of the fabric produced by reducing the number of fabric defects due to distortion of weave, knees, accumulation of excessive lint fiber or fuzz balls which are subsequently woven into the fabric, knots from excessive warp breaks, draw-backs and filling floats.

The sizing process consists of passing the warp through a size box or trough containing a film former, removing excessive film former with squeeze rolls and drying over heated cylinders or in an oven. After drying the warp, the individual ends are separated from one another by a series of bars known as split rods or lease rods. A size which has little adhesion to the yarn will flake off or shed at the lease rods. On the other hand, a size which binds the yarn too firmly together will cause excessive end or yarn breakage.

The sized warp after separation at the lease rods is.

preparation of starch sizing involves adding the starch to cold water under agitation and agitating for 5 to 15 minutes to thoroughly disperse all the starch granules in the water. The resultant slurry is then heated until the starch is gelatinized. Softeners, plasticizers, penetrants, and other adhesive adjuncts may be added to the slurry prior to heating or after the starch has been cooked. The cooked sizing solution is then ready for transfer to the slasher after appropriate temperature adjustment.

With the introduction of various hydrophobics, synthetic fibers such as the polyamides, polyesters, and polyacrylics, new sizing problems were created. Adhesion of conventional starch sizing materials to these fibers was poor and major problems developed due to inadequately protected yarn resulting in low weaving efficiency and poor fabric quality. Similar results were obtained with mixtures of hydrophobic fibers with such natural fibers as cotton, wool and the hydrophilic synthetic fibers such as cellulose acetate, viscose, etc.

3,144,351 Patented Aug. 11, 1964 It is therefore a principal object of this invention to provide an improved method and improved compositions for sizing hydrophobic synthetic yarns. More specifically, it is an object of this invention to provide an improved method of employing starch for the sizing of hydrophobic synthetic yarns. Further objects and advantages will be indicated in the following detailed specification.

It has been discovered that the sizing properties of starches and starch derivatives with hydrophobic warp yarns can be modified and regulated by incorporation in the size solution of a minor proportion of urea to achieve sizing which results in high weaving efficiency. The urea apparently greatly increases the afiinity of starches and starch derivatives for hydrophobic surfaces. This results in greatly increased bonding between the starch film and the yarn fibers. In order to secure the greatest Weaving efficiency it is preferred to use starches having organic groups substituted on the starch polymer chains. For

example, hydroxyethylated starch and acetylated starch,

These starch derivatives are superior sizing materials for hydrophobic warp yarns. By combining the action of starches having superior sizing properties with the bonding action of urea, weaving efficiencies approaching 100% can be attained.

The method of this invention can be advantageously practiced with hydroxyethylated starches and acetylated starches. The processes for producing such starches are well-known, and acetylated and hydroxyethylated starches are commercially available at the present time. The principal variation in such starches is in the degree of hydroxyethylation or acetylation. For the purpose of the present invention, the starch should contain at least 1% by Weight of the hydroxyethyl or acetyl substituent groups. For hydroxyethylated starch, the preferred range is a substitution of 1 to 4%, while for acetylated starches the preferred substitution range is from 2 to 4%. For both hydroxyethylated starches and acetylated starches higher degrees of substitution can be used, even up to substitution levels of 20 to 25%, but for achieving the maximum in its natural granule state so that it is ungelatinized prior to being prepared as a starch size. Other starches and starch derivatives can also be used.

To achieve the objects of this invention, the starch must be employed in conjunction with a minor portion of urea. From as little as 5 parts up to 14 parts of urea per 100 parts of the starch can be used. However, it is preferred to use from 7 to 13 parts by weight of urea per 100 parts of the hydroxyethylated or acetylated starch.

To achieve optimum results, the proportion of urea should be adjusted in relation to the humidity of the weave room. For example, when the relative humidity of the weave room is -95%, the urea content approaching the upper portion of the ranges previously stated can be used to greatest advantage. If the relative humidity of the weave room is 50-65%, the quantity of urea giving optimum results will correspond to the lower portions" of the ranges.

The new sizing compositions described above are effective for all spun hydrophobic fibers or mixtures there-.

of with natural or synthetic fibers. They may be advantageously used with mixed fiber yarns containing as little as 25% of hydrophobic fibers, although they are preferably employed withyarns which contain at least a major portion of the hydrophobic fibers.

or other polyamide yarns, polyester yarns, and polyacrylic It is pre-' The compositions are particularly adapted for the sizing of nylon;

3 yarns. The weight added to the warp during sizing will vary depending upon the fibers in the yarn, and the construction in which the fabric is to be woven. Usually, the weight of the warp will be increased from 5 to 26%.

In the commercial use of the invention, the starch may be dry blended with the urea, and the resulting mixture used to prepare the starch size. The procedure for preparing the size will be substantially the same as for ordinary starch sizes. For example, a hydroxyethylated or an acetylated starch is dispersed in water, and heated until it is completely gelatinized. The urea is preferably present during the gelatinization, but it may be added after the starch has been gelatinized. The concentration of the hydroxyethylated or acetylated starch in the size may vary from 5 to 25%. If desired, softeners, plasticizers, and penetrants may also be incorporated in the size. The temperature of the size during the slashing step may vary considerably depending upon the specific fiber composition of the warp, and the construction of the fabric to be produced from the warp. For example, the size temperature may vary from 100 F. to 210 F.

Sizes prepared from the novel composition of this invention are characterized by uniform viscosity, absence of congealing and skinning properties, absence of foaming properties, excellent stability toward decomposition, high specific adhesion to the hydrophobic fibers, and increased elasticity. As indicated previously, said sizes comprise essentially an aqueous dispersion of the hydroxyethylated or acetylated starch in conjunction with a minor proportion of urea.

The invention is further illustrated by the following specific examples.

EXAMPLE 1 Size Preparation 174 lbs. of a mixture of 12% urea and 88% of an acid modified (medium fluidity) hydroxyethylated corn starch containing 2.2% hydroxyethyl groups was added to a steel kettle containing 70 gallons of cold water containing 7.4 lbs. of a high melting non-sulfonated wax (Seyco Wax C). The slurry was agitated for 15 minutes. Open steam was then applied and the temperature raised to 208 F. in minutes. The temperature was maintained at this point for one hour. The finished volume was 100 gallons. The gelatinized mixture was pumped to a storage kettle and maintained under agitation at 206 F. The viscosity was 102 centipoises (Brookfield Spindle No. l, 50 rpm).

Slashing The above sizing composition was used in a conventional double size box multican slasher to size a warp consisting of 5324 ends of 40/1 yarn comprised of 65% 1.5 d. (Dacron) polyester fiber and combed cotton. The size content of the yarn on a bone dry basis was 17%.

Weaving The warp sized as described was mounted on a loom and drawn in a pattern to weave a fabric having a construction of 112 x 72. Weaving efliciency over the loom life of the warp was 96%.

Repetition of the above experiment without urea resulted in unacceptable weaving efiiciency (below 82%). Repetition of experiment using varying amounts of an acrylic emulsion in place of urea resulted in a maximum eificiency of 88%.

EXAMPLE 2 The procedure of Example 1 was repeated using an acid modified medium viscosity acetylated starch containing 3.5% acetyl groups. Weaving efficiency was 94%.

EXAMPLE '3 The procedure of Example 1 was repeated except that the sizing composition consisted of 200 lbs. of a mixture consisting of 92% of an acid modified (low fluidity) hy- 4 droxyethylated starch (2.0% hydroxyethylation) and 8% of urea. 6 pounds of Seyco Wax C was used.

The yarn sized was 100% 1.5 d. polyester fiber. The warp consisted of 3,012 ends of 22/1 yarn and the fabric had a construction of 64 x 50.

Weaving efiiciency was A comparable trial made without urea could not be woven. Substitution of varying amounts of polyvinyl alcohol for urea in the above gave a maximum weaving efficiency of 87%.

Substantially identical results were obtained when a polyamide (6 d. nylon, 864 ends 4/ 1) was substituted for the polyester fiber in the above example.

EXAMPLE 4 The procedure of Example 1 was repeated except that the sizing composition consisted of 110 lbs. of a mixture consisting of 90% of an acid modified (low fluidity) hydroxyethylated starch (3% hydroxyethylation) and 10% of urea. 6 pounds of wax was used.

The yarn sized was 2 d. acrylic fiber. The warp consisted of 3200 ends of 20/1 yarn and the fabric woven had a blanket construction of 43 x 39. The size content of the yarn on a bone dry basis was 9%. Weaving efficiency was 94%.

The term synthetic yarn as used herein is intended to refer to synthetic fiber spun yarn.

While this invention has been described in the foregoing specification in relation to certain specific examples thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to other embodiments, and that many of the details described herein can be varied considerably without departing from the basic principles of the invention.

I claim:

1. In the sizing of hydrophobic synthetic yarn prior to weaving, said yarn being selected from the class consisting of nylon yarn, polyester polymer yarn, and polyacrylic yarn, the improved method comprising contacting said yarn with an aqueous dispersion of a starch derivative selected from the group consisting of hydroxyethylated starch containing at least 1% by weight of the hydroxyethyl groups and acetylated starch containing at least 1% by weight of the acetyl groups, said aqueous dispersion also containing from 5 to 14 parts of urea per 100 parts by weight of said starch derivative.

2. In the sizing of hydrophobic synthetic yarn prior to weaving, said yarn being selected from the class consisting of nylon yarn, polyester polymer yarn, and polyacrylic yarn, the improved method comprising contacting said yarn with an aqueous dispersion of a starch derivative selected from the group consisting of hydroxyethylated starch and acetylated starch, said aqueous dispersion also containing from 7 to 13 parts of urea per 100 parts by weight of said starch derivative, said hydroxyethylated starch containing from about 1 to 4% by weight of hydroxyethyl groups, and said acetylated starch contalning from about 2 to 4% by weight of acetyl groups.

3. The method of claim 2 in which said hydrophobic synthetic yarn is nylon.

4. The method of claim 2 in which said hydrophobic synthetic yarn is a polyester polymer yarn.

5. The method of claim 2 in which said hydrophobic synthetic yarn is a polyacrylic yarn.

References Cited in the file of this patent UNITED STATES PATENTS 2,023,973 Pierson Dec. 10, 1935 2,192,218 Bosland Mar. 5, 1940 2,192,219 Bosland Mar. 5, 1940 2,980,556 McClelland Apr. 18, 1961 3,03 6,935 Lolkema et a1. May 29, 1962 

1. IN THE SIZING OF HYDROPHOBIC SYNTHETIC YARN PRIOR TO WEAVING, SAID YARN BEING SELECTED FROM THE CLASS CONSISTING OF NYLON YARN, POLYESTER POLYMER YARN, AND POLYACRYLIC YARN, THE IMPROVED METHOD COMPRISING CONTACTING SAID YARN WITH AN AQUEOUS DISPERSION OF A STARCH DERIVATIVE SELECTED FROM THE GROUP CONSISTING OF HYDROXYETHYLATED STARCH CONTAINING AT LEAST 1% BY WEIGHT OF THE HYDROXYETHYL GROUPS AND ACETYLATED STARCH CONTAINING AT LEAST 1% BY WEIGHT OF THE ACETYL GROUPS, SAID AQEUOUS DISPERSION ALSO CONTAINING FROM 5 TO 14 PARTS OF UREA PER 100 PARTS BY WEIGHT OF SAID STARCH DERIVATIVE. 